This invention relates to a hydraulic coupling device for a multi-line hose. The invention is useful in the hydraulic distribution systems used in underground mine workings, particularly for hydraulic advanceable mine roof support assemblies and other hydraulic appliances.
Systems are known in which numerous hydraulic lines are bunched together to form multi-line hoses, which are interconnected by means of generally cylindrical plug couplings. A known plug coupling includes a coupling device having a plurality of plug pins, and a connector having a plurality of sockets which mate with the plug pins, the coupling device and the connector being attached to respective multi-line hoses. (see DE-OS No. 2059576).
This known type of coupling device has a casing which houses the plug pins, the plug pins being supported by a holder within the casing. Each of the plug pins is attached to the holder in such a manner as to permit a slight amount of axial and radial play so that the plug pins can easily be positioned within the sockets of the connector, without forcing or deformation. The holder is a disc provided with apertures for receiving the plug pins, the apertures lying on a common pitch circle. Each of the plug pins has a collar which engages one side of the disc, the plug pins being retained against the disc by means of small circlips which snap into grooves in the plug pins, the circlips engaging the other side of the disc.
Since, in general, the hoses have a relatively large number of lines, for example sixteen, the expense of manufacturing and assembling the plug pins in the disc using the small circlips, is considerable. Moreover, there is a danger of damage or destruction of the relatively weak circlips under the high operational forces.
Another known type of coupling device has plug pins which are held in position between a holder and a retainer, both of which are disc-like plates. The circumferential edge of the retainer engages the inner edges of the collars of the plug pins, and the retainer is bolted to the holder so that the inner edges of the collars are clamped between the retainer and the holder. Unfortunately, the firm clamping of the collars between the two disc-like plates can lead, during the tightening up of the two plates, to distortion of the relatively weak plug pins. This possibility of distortion is increased by the clamping forces acting only on the inner edges of the collars. Moreover, this type of coupling device is a relatively large and heavy construction, since the two plates lie at a relatively large axial separation.